Author Archives: Tim

Is Spring RestTemplate Thread Safe

Is Spring RestTemplate Thread Safe? The only correct answer to this question is: No A quick look at the source (the link is tied to a specific version so the line number is always correct) on line 230 shows the … Continue reading

Posted in Software Engineering | Comments Off on Is Spring RestTemplate Thread Safe

Hadoop Terasort VirtualBox benchmarks

Setup: 3-node hadoop (hdp v2.6.1), installed via Ambari 2.5.1 and running in VirtualBox 5.1 on one physical machine. The terasort is traditionally run on 1 terabyte of random data (SIZE=10,000,000,000). In 2008, Yahoo! ran terasort on 1TB of data in … Continue reading

Posted in Storage | Comments Off on Hadoop Terasort VirtualBox benchmarks

Secret Share 1.4.3 on Maven Central

Secret Share in Java on Maven Central Just completed a release of the Secret Share in Java project to Maven Central. Search for it using search.maven.org. Or, go to SecretShare-1.4.3 directly. GroupId: com.tiemens ArtifactId: secretshare Version: 1.4.3 This release adds … Continue reading

Posted in Software Project | Comments Off on Secret Share 1.4.3 on Maven Central

Real World Debugging Exercise

Just completed the Real World Debugging Exercise. It is a static page on this site (just like the Lot Area Calculator).

Posted in Uncategorized | Comments Off on Real World Debugging Exercise

VirtualBox USB Flash for ZFS

To set up your USB Flash drives as pass-through in VirtualBox, here is what you can do. Next, plug in your flash drive and record its device. For me, it was /dev/sde. Look in /var/log/syslog, or dmesg output, for the … Continue reading

Posted in ZFS | Comments Off on VirtualBox USB Flash for ZFS

ZFS Flash Drives

As an experiment, I created a small (8GB) ZFS volume in a mirror configuration using two 8GB USB Flash drives. The purpose was to put “small, but really important things” on this storage system. It actually ended up being two … Continue reading

Posted in ZFS | Comments Off on ZFS Flash Drives

iptables flush and ssh

Fun lesson from today: don’t blindly clear/flush your iptables. If you are remotely managing a system, then make sure you run this: sudo iptables -P INPUT ACCEPT sudo iptables -P FORWARD ACCEPT sudo iptables -P OUTPUT ACCEPT before you run … Continue reading

Posted in Software Engineering, Ubuntu | Comments Off on iptables flush and ssh

Kids Game Build

The goal of this machine was to replace the highly unreliable kids computer (Portable Power Build). First the GPU went, then the HDD started showing errors. Finally the MB voltage started to act up. The net result was that the … Continue reading

Posted in Computer Builds, Core-i5 | Comments Off on Kids Game Build

Ubuntu 16.04 Vnc and VirtualBox Resolution

As posted for 14.04, here are the steps to getting a larger VNC connection to your Ubuntu 16.04 virtual machine: Desktop Sharing Desktop Sharing is back as an item in 16.04 desktop. Just bring up the search, type “Desktop Sharing”. … Continue reading

Posted in Ubuntu | Comments Off on Ubuntu 16.04 Vnc and VirtualBox Resolution

Brother HL-2170W wifi

Having upgraded the wifi device, and changing the SSID and passphrase, the Brother HL-2170W printer needed to be updated. First, the “easy button” just failed. Never worked. Which I recall happened the last time I set up this printer. Next … Continue reading

Posted in Uncategorized | Comments Off on Brother HL-2170W wifi